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SSL benefits a user entering a password on a public network. A MITM attack against your renewal does not expose your private key. I don’t think that causes the

SSL benefits a user entering a password on a public network. A MITM attack against your renewal does not expose your private key. I don’t think that causes the harm the article suggests.

1718627440 1y ago
It however does allow to intercept all future connections to your webserver until you recognize it and publish a revocation certificate.
- Avamander 1y ago
  No. The private key does not leave the server, you can't use the certificate without it.
  - 1718627440 1y ago
    When you MITM a certificate request the attacker can provide it's own key.
    - Avamander 1y ago
      That's not what you described though, because then you wouldn't be able to revoke it once you notice it. You can't revoke a certificate without its private key. (Then it's only the CA who could if you convince them of the misissuance. Which probably means proving current access right now and asking the CA to revoke it.) In any case if someone can become the thing you're trying to validate, be it access to an IP address or some DNS zone, you're kinda out-of-luck anyways. Though WebPKI has CT, which will give you some insight into it, unlike everything else out there.
      - 1718627440 1y ago
        Yeah I thought you could issue an exclusive certificate that revokes all others, guess I am wrong. > In any case if someone can become the thing you're trying to validate That's kind of the thing that certificate validation is supposed to solve, an attacker posing as you. That's why the article says it's useless in theory. In practice MITM at validation is harder than in use, but it does have issues. That's why Let's Encrypt wasn't the default model.
        Avamander 1y ago
        > That's kind of the thing that certificate validation is supposed to solve, an attacker posing as you [...] No, not really. Certificates get issued to hostnames and less frequently, IP addresses. If someone has full control over that resource then what's the actual difference between "you" and "attacker"? Should they run a malware scan too that your server is not compromised? It's not a thing a CA can solve if you've completely lost control of your infrastructure.
        1718627440 1y ago
        OK, I misunderstood you. I interpreted: > if someone can become the thing you're trying to validate as someone able to impersonate you, not someone actually owning your server. For the latter you're right.

SSL benefits a user entering a password on a public network. A MITM attack against your renewal does not expose your private key. I don’t think that causes the harm the article suggests.

1718627440 1y ago

It however does allow to intercept all future connections to your webserver until you recognize it and publish a revocation certificate.

Avamander 1y ago
No. The private key does not leave the server, you can't use the certificate without it.
- 1718627440 1y ago
  When you MITM a certificate request the attacker can provide it's own key.
  - Avamander 1y ago
    That's not what you described though, because then you wouldn't be able to revoke it once you notice it. You can't revoke a certificate without its private key. (Then it's only the CA who could if you convince them of the misissuance. Which probably means proving current access right now and asking the CA to revoke it.) In any case if someone can become the thing you're trying to validate, be it access to an IP address or some DNS zone, you're kinda out-of-luck anyways. Though WebPKI has CT, which will give you some insight into it, unlike everything else out there.
    - 1718627440 1y ago
      Yeah I thought you could issue an exclusive certificate that revokes all others, guess I am wrong. > In any case if someone can become the thing you're trying to validate That's kind of the thing that certificate validation is supposed to solve, an attacker posing as you. That's why the article says it's useless in theory. In practice MITM at validation is harder than in use, but it does have issues. That's why Let's Encrypt wasn't the default model.
      - Avamander 1y ago
        > That's kind of the thing that certificate validation is supposed to solve, an attacker posing as you [...] No, not really. Certificates get issued to hostnames and less frequently, IP addresses. If someone has full control over that resource then what's the actual difference between "you" and "attacker"? Should they run a malware scan too that your server is not compromised? It's not a thing a CA can solve if you've completely lost control of your infrastructure.
        1718627440 1y ago
        OK, I misunderstood you. I interpreted: > if someone can become the thing you're trying to validate as someone able to impersonate you, not someone actually owning your server. For the latter you're right.